Problem with Qt Designer - pglive integration for real-time plotting

Question

I followed the tutorial on the pglive docs and I was able to have a real-time sine plot on my computer. Then I used an arduino to stream some random number through the serial port and I was able to read and plot the data using pglive.

Now I want to integrate a custom gui made with Qt Designer.

This is the code I'm trying to run:

import sys
from math import sin
from threading import Thread
from time import sleep
from PyQt5.QtWidgets import QApplication
from PyQt5 import QtWidgets, QtCore, uic
from pglive.sources.data_connector import DataConnector
from pglive.sources.live_plot import LiveLinePlot
from pglive.sources.live_plot_widget import LivePlotWidget
import serial

arduino = serial.Serial(port='COM17', baudrate=9600, timeout=.1) 

app = QApplication(sys.argv)
running = True

ui = uic.loadUi('test.ui')

plot_widget = ui.plot1 # LivePlotWidget(title="Line Plot @ 100Hz")
# plot_curve = LiveLinePlot()
# plot_widget.addItem(plot_curve)
# DataConnector holding 600 points and plots @ 100Hz
data_connector = DataConnector(ui.plot1, max_points=600, update_rate=100)
# data_connector = DataConnector(plot_curve, max_points=600, update_rate=100)

def sin_wave_generator(connector):
    """Sine wave generator"""
    x = 0
    while running:
        x += 1
        data = arduino.readline().decode("utf-8") # retrieve serial data from feather
        values = data.split(",") # split at commas
        data_point = float(values[0])
        # Callback to plot new data point
        connector.cb_append_data_point(data_point, x)
        sleep(0.01)

plot_widget.show()
Thread(target=sin_wave_generator, args=(data_connector,)).start()
app.exec()
running = False

Basically, I commented the plot_curve and plot_widget lines, and loaded the ui onto the plot_widget variable.

The gui is just a widget (named plot1) that I promoted to LivePlotWidget and set header file to pglive.sources.live_plot_widget as explained again by pglive guys in their docs.

However, what I obtain is the following:

Traceback (most recent call last):
  File "C:\Users\New Wyss User\AppData\Roaming\Python\Python311\site-packages\pglive\sources\live_plot.py", line 134, in <lambda>
    plot.slot_roll_tick = lambda data_connector, tick: plot.plot_widget.slot_roll_tick(data_connector, tick)
                                                       ^^^^^^^^^^^^^^^^
  File "C:\Users\New Wyss User\AppData\Roaming\Python\Python311\site-packages\pyqtgraph\widgets\PlotWidget.py", line 82, in __getattr__
    raise AttributeError(attr)
AttributeError: plot_widget
Traceback (most recent call last):
  File "C:\Users\New Wyss User\AppData\Roaming\Python\Python311\site-packages\pglive\sources\live_plot.py", line 121, in <lambda>
    plot.slot_new_data = lambda y, x, kwargs: plot.setData(x, y, **kwargs)
                                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: setData(self, key: int, value: Any): argument 1 has unexpected type 'numpy.ndarray'

Any suggestion? Thanks!

Answer 1

Bingo. I found the issue. This works:

import sys
from math import sin
from threading import Thread
from time import sleep

from PyQt5.QtWidgets import QApplication
from PyQt5 import QtWidgets, QtCore, uic

from pglive.sources.data_connector import DataConnector
from pglive.sources.live_plot import LiveLinePlot
from pglive.sources.live_plot_widget import LivePlotWidget


import serial

arduino = serial.Serial(port='COM17', baudrate=9600, timeout=.1) 

app = QApplication(sys.argv)
running = True

ui = uic.loadUi('test.ui')

#plot_widget = ui.plot1 # LivePlotWidget(title="Line Plot @ 100Hz")
plot_curve = LiveLinePlot()
ui.plot1.addItem(plot_curve)
# DataConnector holding 600 points and plots @ 100Hz
data_connector = DataConnector(plot_curve, max_points=600, update_rate=100)
# data_connector = DataConnector(plot_curve, max_points=600, update_rate=100)


def sin_wave_generator(connector):
    """Sine wave generator"""
    x = 0
    while running:
        x += 1
        data = arduino.readline().decode("utf-8") # retrieve serial data from feather
        values = data.split(",") # split at commas
        data_point = float(values[0])
        # Callback to plot new data point
        connector.cb_append_data_point(data_point, x)

        sleep(0.01)


ui.show()
Thread(target=sin_wave_generator, args=(data_connector,)).start()
app.exec()
running = False

Hope this will help others with the same doubts!